Many kinds of businesses work just fine on the "pay it once" model. You produce a pair of shoes, I buy that pair of shoes, and we are done. This classic, standard model doesn't have to be unsustainable.
In particular, look at the gig economy. Thousands of freelance programmers, designers, artists, and tradesmen are making a living through one-time invoices.
I may be an outlier, as I don't subscribe to much of anything on a recurring basis except Netflix and Google Apps. In the real world, I have a mortgage, not rent, and I own my car, I don't lease it.
And to GP: Patreon does give you a "guilt trip" asking for a cause for your cancellation of a monthly subscription immediately after donating, but it's easy and it works.